MIAB welding is a forge-welding process in which a welding arc is established in a gap between the parts to be welded, and the arc is moved by means of a magnetic field. In the MIAB welding of steel pipes, the square edged or otherwise prepared pipe ends to be welded are aligned axially and separated by a small gap, and a welding arc established in the gap. A magnetic field is then superimposed on the gap, causing the arc to rotate at high speed around the gap. After the ends are heated, they are pressed together causing plastic and molten metal present on the heated surfaces to be forced out of the joint, along with oxides and other impurities. A high quality weld is thus produced.
Although MIAB welding has been proposed for pipelines, prior art methods for its implementation have been found wanting.